Methods and apparatus for selective spring pre-load adjustment

ABSTRACT

A method and apparatus for a suspension comprising a spring having a threaded member at a first end for providing axial movement to the spring as the spring is rotated and the threaded member moves relative to a second component. In one embodiment, the system includes a damper for metering fluid through a piston and a rotatable spring member coaxially disposed around the damper and rotatable relative to the damper.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. provisional patent applicationSer. No. 61/161,552, filed Mar. 19, 2009, and U.S. provisional patentapplication Ser. No. 61/161,620, filed Mar. 19, 2009. Each of theaforementioned related patent applications is herein incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to auser-adjustable spring for use in a shock absorber.

2. Description of the Related Art

Integrated damper/spring vehicle shock absorbers often include a damperbody surrounded by a mechanical spring. The damper often consists of apiston and shaft telescopically mounted in a fluid filled cylinder. Themechanical spring may be a helically wound spring that surrounds thedamper body. Various integrated shock absorber configurations aredescribed in U.S. Pat. Nos. 5,044,614; 5,803,443; 5,553,836; and7,293,764; each of which is herein incorporated, in its entirety, byreference.

The spring mechanism of many shock absorbers is adjustable so that itcan be preset to varying initial states of compression. In that way theshock absorber can be adjusted to accommodate heavier or lighter carriedweight, or greater or lesser anticipated impact loads. In motorcycleracing, particularly off-road racing, shock absorbers may be adjustedaccording to certain rider preferences.

U.S. Pat. No. 5,044,614 (“the '614 patent”) shows a damper body carryinga thread 42. A helical spring 18 surrounds the damper body where the twoform an integrated shock absorber. The compression in the helical spring18 may be pre-set by means of a nut 48 and a lock nut 50. Because thenut 48 and lock nut 50 must be relatively torqued to prevent nut 50rotation upon final adjustment, the shock absorber must typically beremoved from its vehicle in order to allow torquing wrench access. Oncethe spring 18 is in a desired state of compression, lock nut 50 isrotated, using a wrench, up against nut 48 and tightened in a bindingrelation therewith.

The system described in the '614 patent requires that the user be ableto access a large amount of the circumference of the shock absorber, andspecifically the nut 48 and lock nut 50, with a wrench (e.g. col. 4,lines 15-17). Unfortunately many shock absorbers, as mounted on acorresponding vehicle, are fairly inaccessible, and have limitedsurrounding wrench space because of other surrounding vehicle hardwareand/or, as in the instant case, a separate damping fluid reservoir or“piggyback.” What is needed is a shock absorber having a spring that canbe readily adjusted while the shock absorber is mounted on a vehicle.What is needed is a motorcycle “monoshock” having a spring that can beeasily adjusted without removing the shock from the motorcycle. What isneeded is a shock absorber having a spring where the state of springadjustment is constantly indicated and easily visible while the shock ismounted on a vehicle.

SUMMARY

The present invention generally relates to a suspension comprising aspring assembly having a threaded member at a first end for imposingaxial movement in the spring as the spring is rotated and therebyrotating the threaded member relative to a second component. In oneembodiment, the system includes a damper for metering damping fluid anda rotatable spring member coaxially disposed around the damper androtatable relative to the damper. In one embodiment an adjustmentassembly includes a spring adjustment nut (e.g. follower nut) and clampwith the adjustment nut disposed on a threaded portion of the secondcomponent. When the clamp is loosened, the adjustment or “follower” nutrotates with the spring which is rotated by a user and the rotationthereby compresses or decompresses the spring as the nut moves axially(by thread pitch) along the threaded second component. In oneembodiment, the clamp includes an indicator that cooperates withmarkings on the second component to indicate the compression state ofthe spring.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description maybe had by reference to embodiments, some of which are illustrated in theappended drawings. It is to be noted, however, that the appendeddrawings illustrate only typical embodiments of this invention and aretherefore not to be considered limiting of its scope, for the inventionmay admit to other equally effective embodiments.

FIG. 1 is a perspective view of a shock absorber having auser-adjustable spring.

FIG. 2 is an exploded view of a follower nut and clamp, and 2A is asection view thereof.

FIG. 3 is an enlarged view showing an interface between the clamp,follower nut and spring.

FIG. 4 is a perspective detailed view of the shock absorber.

DETAILED DESCRIPTION

FIG. 1 shows an embodiment of a reservoir type shock absorber 100. Theshock absorber includes a second component, such as in this embodiment adamper body 120, with a rod 125 extending therefrom and a reservoir 150is in fluid (e.g. damping fluid such as hydraulic oil) communicationwith the damper body 120. The shock further includes a helical spring175 annularly disposed about the damper body 120 and captured axiallybetween a bottom clip 180 at a lower end and an adjuster assembly 200 atan upper end. An outer surface of the damper body 120 includes threads190 that facilitate rotation of nut 210 and corresponding axial movementof the adjuster assembly 200 relative to the body 120.

One embodiment of the adjuster assembly 200 is best appreciated withreference to all of the Figures and comprises a follower nut 210 and aclamp 250. In one embodiment the follower nut 210 includes a pin 215 forfitting into a hole 216 (shown in FIG. 2) in a flange of the nut 210.Referring to FIG. 3, the pin 215 rotationally indexes the follower nut210 to the spring 175 at an interface 300 between an abrupt end 470 ofthe wound wire and an upwardly inclined upper surface of the same woundwire in the coil preceding (i.e. directly underneath) the abrupt end 470of the helical spring 175. In one embodiment, pin 215 extends axially(i.e. parallel to the longitudinal axis of the shock absorber 100)downward from follower nut 210 and extends into the interface space 300.Due to interference between the pin 215 and the abrupt end 470 of spring175 in one direction (referring to FIG. 3) and the helical angle of thespring wire in the other direction where the end and the angle combinedform an axial recess at an upper end of the spring 175, rotation of thespring 175 will interfere with the pin (or key or tooth) 215 and imparta rotational force (via the pin 215) to the follower nut 210.Conversely, rotation of the follower nut 210 will carry the pin 215 anda rotational force will be correspondingly transmitted to the spring175. In one embodiment (not shown) an upper portion of the spring 175adjacent the abrupt end 470 is tapered to increase the surface contactbetween the spring and a lower end of the follower nut 210 (i.e. thespring end is ground “flat”). In one embodiment (not shown) theflattened last coil portion of the upper end of the spring includes anaxial hole drilled therein for receiving the portion of pin 215 thatprotrudes from hole 216. In one embodiment the upper end of the springis castellated and the lower surface 212 of the nut 210 is castellatedsuch that the castellations of the nut and the spring areinterengageable for rotationally fixing the nut 210 to the spring 175.In one embodiment, the nut 210 includes a ratcheting pawl set on a lowersurface thereof and the spring includes suitable beveled one waycastellations on an upper surface thereof (or vice versa) and the springand the nut are therefore rotationally engaged in one rotationaldirection only (depending on the sense of the ratchet set) andrelatively freely rotatable in the other rotational direction. In oneembodiment, the spring 175 is rotatable in relation to the bottom clip180. In another embodiment the bottom clip 180 is bearing-mounted (e.g.with a race of ball bearings disposed between a lower end of the springand an upward facing surface of the bottom clip 180 in axially abuttingrelation to each) to a shock mount 195 and thereby facilitates easierrotation of the spring 175 relative to the damper body 120 (by reducingthe relative apparent coefficient of friction between the bottom clipand the lower end of the spring). In one embodiment, the springcomprises a plurality of springs axially abutted one with another whereeach of the springs has a different spring rate. In one embodiment, atleast one spring of a shock absorber is wound having a compound springrate. It is worth noting that as the spring 175 is placed in greaterstates of compression, the friction force between the spring 175 and itsaxial abutments at the clip 180 and the follower nut 210 are increased.

While the follower nut 210 is a separate component in some embodiments,it will be understood that the nut can be integral with the spring 175whereby one end of the spring is therefore effectively threaded to thedamper housing and axially adjustable upon rotation of the spring whilean opposite end of the spring is axially fixed but rotationally movablerelative to the damper body. In one embodiment, the clamp member canalso be formed to simply include a threaded member, for instance, thatinteracts with the damper body to prevent rotation between the threadsof the integral spring/nut/clamp and the threaded damper body. In oneembodiment, the bottom portion 180 includes a cylindrical member, orbody, (not shown) axially and upwardly disposed within and along thespring 175. In one embodiment the cylindrical member is threaded alongan axial exterior length thereof. In one embodiment an adjustmentassembly 200 is located between bottom clip or annular “lip” 180 and alower end of the spring 175. Much as has been previously described inrelation to threads 190 and the nut 210, in one embodiment the threads211 on an inner diameter of nut 210 are engaged with threads on an outerdiameter of the cylindrical member (not shown). The pin 215 engages arecess 300 at a lower end of the spring 175. As previously described,rotation of the spring 175 correspondingly rotates the nut 210, via pin215, and the nut 210 translates axially along the cylindrical memberthereby increasing or decreasing the compression in the spring 175depending on the direction of rotation and the directional “sense” ofthe threads. In one embodiment the cylindrical member (not shown) has aninner diameter that is larger than the outer dimensions of the springand is disposed axially upward along the shock and outside of thespring. A nut is threaded on an outer diameter thereof and engaged withan end of the spring and the cylinder is threaded on an inner diameterthereof and the nut, cylinder and spring cooperate as principallydescribed herein to facilitate adjustment of compression in the spring.In one embodiment the spring includes an assembly 200 and correspondingthreaded sections (e.g. 190, cylindrical member) at each of its ends. Inone embodiment the threads at each end are opposite in “sense” so thatrotation of the spring increases or decreases compression in the springtwice as fast as a single threaded end version. In one embodimentthreads at one end are of a different pitch than threads at the otherend of the spring 175.

FIGS. 2 and 2A show details of embodiments of the clamp 250 and followernut 210. In one embodiment the follower nut 210 is cylindrical (withvarying diameters along its length) generally with a cut though or split220, giving it the form of a “C” ring. The clamp 250 is also in the formof a “C” ring, being generally cylindrical and having its own cut orsplit 230. As can be seen in FIG. 2A, the clamp 250 fits over thefollower nut 210. In one embodiment the clamp 250 is expandedelastically at the split 230 to clear a lip 212 at a smaller-diameterend of the follower nut. Once the clamp 250 has cleared the lip, it isreturned to a “relaxed” state surrounding a portion of the nut 210 andis rotationally movable relative thereto. The clamp 250 may then rotateabout the follower nut 210 (and the follower nut 110 may rotate withinthe clamp 250) but the clamp 250 is retained axially on the follower nut210 by lip 212. In one embodiment a screw 260, with a suitable washer isinserted into the clamp 250 but not tightened until such time asrotational and axial retention of the follower nut 210 on the damperbody 120 (e.g. because spring adjustment is complete) is desired. In oneembodiment, the adjuster assembly 200, with its nut 210 and clamp 250,is threaded onto threads 190 of body 120, and is moved axially (e.g. byrotation of the threaded (211) nut 210 about threads 190) until anindicator 255 (best seen in FIGS. 2 and 4) formed on the clamp 250 islocated adjacent the reservoir 150. In one embodiment a curved surface256 of the indicator 255, corresponding generally to the curved shape ofthe reservoir body is aligned with the exterior of the reservoir 150 andthe follower nut 210 and clamp 250 may be axially translated furthertoward a lower end of the shock 100 by rotation of follower nut 210(while clamp 250 remains aligned with reservoir 150 via indicator 255).Tightening the screw 260 “closes” the C-shaped clamp 250 andcorrespondingly closes the follower nut 210 thereby preventing thefollower nut 210 from rotating on the threaded surface 190 of the damperbody 120, and therefore frictionally (e.g. as a clamp) locking the nut210 to the damper body and thus retaining the user-adjusted compressionin the spring 175.

In one embodiment the indicator 255 connected on clamp 250, androtationally fixed relative to the clamp 250, serves at least twopurposes. Its curved surface 256 conforms to a portion of an exterior ofthe reservoir 150, thereby preventing rotation of the clamp 250 duringrotation of the spring 175. As such the orientation of screw 260 ismaintained relative to the shock absorber and the vehicle on which theshock absorber is mounted. Correspondingly, the screw 260 is maintainedin an accessible location for tightening and loosening to facilitatespring 175 adjustment while the shock absorber remains mounted on thevehicle. Second, the indicator 255 serves to indicate axial compressionstate of the spring 175 relative to a scale 400 (referring to FIG. 4).

In one example, the clamp 250 is loosened by inserting an appropriatehex or blade type wrench or screw driver (not shown) through apredetermined shock absorber access space available in the vehicle(vehicle such as a monoshock rear shock motorcycle) and rotating screw260 counterclockwise (assuming a right hand thread screw 260) to loosenthe clamp. Once the clamp 250 is loose, the spring 175 can be manuallygripped, through the access space, by a user and rotated manually, forexample, in one embodiment having right hand threads 190 from the topaxial view of the shock absorber, clockwise as viewed from the upperend, to increase compression or pre-load in the spring 175. In thatembodiment rotating the spring 175 counterclockwise as viewed from abovereduces pre-load of the spring 175 (or vice versa depending on the senseof threads 190). As previously described, such rotation of the spring175 causes rotation of the follower nut 210 and corresponding axialtranslation of the follower nut 210 (based on the pitch of the threads190) relative to the damper body 120 and along threads 190. Axialmovement of the follower nut 210, relative to non-axially moving bottomclip 180, increases or decreases compression pre-load in spring 175. Inone embodiment, when the desired pre-load is obtained, as indicated bymovement of the indicator 255, which moves axially with the nut 210,relative to the scale 400, the clamp 250 is retightened by rotatingscrew 260 clockwise. It should be noted that the scale 400 may be placedon any suitable and axially static component relative to the followernut 210/clamp 250 and the indicator 255 may be structured to “point”appropriately thereto. In one embodiment the numerical markers on thescale 400 are indicative of a percentage of compression preload in thespring. In one embodiment, the scale and indicator are visible from anexterior of an assembled vehicle with the shock absorber having thescale and indictor mounted thereon. In one embodiment, the scale 400 andindicator 255 “pair” comprise a longitudinal wire coil and permanentmagnet. Position of the magnet relative to the coil is indicated by astate of current through the coil and can be calibrated to correspond toa state of spring compression. In one embodiment the “scale/indicator”pair comprises a proximity sensor and a datum structure. In oneembodiment an electronic “scale/indicator” pair is connected to atransmission circuit having wireless protocol capabilities, such asGarmin's ANT plus, and shock spring compression data is transmitted inreal time or in packets to a user interface/output device such as forexample Garmin's 705 edge GPS enabled computer. In one embodiment theshock absorber is a monoshock and is accessible and visible, whilemounted in a functional position, through a limited access space of themonoshock equipped vehicle.

While the foregoing is directed to certain embodiments of the presentinvention, other and further embodiments of the invention may be devisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

The invention claimed is:
 1. A vehicle suspension comprising: a springannularly disposed about a damper body, the spring comprising: a set ofcoils having a first end and a second end, wherein the outer surface ofthe damper body comprises threads, wherein the spring has a threadedmember rotationally indexed thereto by a pin member, a first end of thepin member being fixedly inserted into a hole of the threaded member anda second end of the pin member positioned at an interface between afirst end of the spring and an upwardly inclined upper surface of thespring in a coil preceding and directly underneath the first end of thespring, wherein the threaded member moves relative to the threads of thedamper body and provides axial movement to the first end of the springas the spring is rotated.
 2. The suspension of claim 1, wherein thespring is axially constrained at the second end relative to at least aportion of the damper body.
 3. The suspension of claim 2, wherein thethreaded member is a follower nut.
 4. The suspension of claim 3, whereinthe follower nut is rotationally fixable in a predetermined axialposition relative to the damper body to which it is threaded.
 5. Thesuspension of claim 4, whereby rotatable fixing is provided with aclamp, the clamp circumferentially housing the follower nut and fixableto the nut in a manner causing interference between threads of the nutand the threads of the damping body.
 6. A suspension system with auser-adjustable spring member, the suspension system comprising: acylindrical body, an outer surface of the cylindrical body comprisingthreads; a rotatable spring member coaxially disposed around thecylindrical body, the rotatable spring member rotatable relative to thecylindrical body and comprising a set of coils having a first end and asecond end; and a follower nut disposed in threaded engagement with thethreads of the cylindrical body and abutting a first end of therotatable spring member, wherein the follower nut is rotationallyindexed to the rotatable spring member by a pin member, wherein the pinmember has a first end and a second end, wherein the first end of thepin member is fixedly inserted into a hole of the threaded member and asecond end of the pin member is positioned at an interface between afirst end of the rotatable spring member and an upwardly inclined uppersurface of the rotatable spring member in a coil preceding and directlyunderneath the first end of the rotatable spring member.
 7. Thesuspension system of claim 6, wherein the follower nut is constructedand arranged to affect compression of the rotatable spring member whiletranslating axially along the threads threads.
 8. The system of claim 7,further including a clamp, the clamp constraining the follower nut in arotational position corresponding to a desired amount of springcompression.
 9. The system of claim 6, whereby interference between thepin member and the rotatable spring member causes the rotatable springmember and follower nut to rotate together.
 10. The system of claim 6,wherein at least one of the rotatable spring member and follower nutrotates as the other of the rotatable spring member and follower nut ismanually rotated.
 11. The system of claim 8, wherein the axial positionof the follower nut is indicated relative to an adjacent component ofthe suspension system.
 12. The system of claim 11, wherein the adjacentcomponent is a reservoir operable with a damper.
 13. The system of claim11, wherein one of the clamp and adjacent member has an indicator andone of the clamp and adjacent member has a scale, the indicator andscale operable to indicate the amount of spring compression.
 14. Amethod for adjusting a vehicle suspension comprising: freeing a springadjustment nut so that it is rotatable relative to a suspension body ofa suspension component; rotating a spring about the suspension body andthereby rotating the spring adjustment nut, wherein the spring isannularly disposed about the suspension body and comprises a set ofcoils having a first end and a second end, wherein the outer surface ofthe suspension body comprises threads, wherein the spring has a threadedmember rotationally indexed thereto by a pin member, a first end of thepin being fixedly inserted into a hole of the threaded member and asecond end of the pin positioned at an interface between a first end ofthe spring and an upwardly inclined upper surface of the spring in acoil preceding and directly underneath the first end of the spring,wherein upon the rotating the spring, the threaded member moves relativeto the threads of the suspension body and provides axial movement to thefirst end of the spring as the spring is rotated; and restraining thespring adjustment nut from rotation about the suspension body.
 15. Themethod of claim 14, wherein the spring adjustment nut is freed byloosening a clamp that retains the spring adjustment nut in a rotationalposition relative to the suspension body.
 16. The method of claim 15,wherein rotation of the spring adjustment nut is due to an engagementbetween the spring adjustment nut and the spring.
 17. The method ofclaim 14, further including the step of determining an amount ofrotation on an indicator and an adjacent scale.
 18. An adjustmentapparatus for a motorcycle shock absorber, comprising: a springadjustment nut abutting a compression spring of a rear shock, whereinrotation of the spring adjustment nut affects the amount of compressionin the compression spring, wherein the compression spring is annularlydisposed about a damper body and comprises a set of coils having a firstend and a second end, wherein the surface of the damper body comprisesthreads; a clamp substantially circumscribing the spring adjustment nutand comprising a fastener; and a pin rotationally indexing the springadjustment nut to the compression spring in at least one rotationaldirection, wherein a first end of the pin is fixedly inserted into ahole of the spring adjustment nut and a second end of the pin ispositioned at an interface between a first end of the compression springand an upwardly inclined upper surface of the compression spring in acoil preceding and directly underneath the first end of the compressionspring, wherein the spring adjustment nut moves relative to the threadsof the damper body and provides axial movement to the first end as thecompression spring is rotated.
 19. The adjustment apparatus of claim 18,wherein the spring adjustment nut is in a threaded relationship with thedamper body and axially movable relative thereto.
 20. The adjustmentapparatus of claim 18, further including an indicator for indicating anamount of spring compression.
 21. The adjustment apparatus of claim 18,wherein the fastener and the compression spring are at least partiallyaccessible by a user of the motorcycle.